Progression of atherosclerosis in smokers: a longitudinal nation-wide serial angiography study

Abstract

Abstract Introduction Smoking is a modifiable risk factor for coronary artery disease (CAD). Cross-sectional studies have shown that prevalence of CAD is higher among smokers as is incidence of myocardial infarction. However, few studies have assessed how smoking affects the incidence of coronary artery plaque progression. Purpose To investigate how CAD progress in smokers. Method All coronary artery segments with <50% luminal stenosis in patients having a first-time coronary angiogram between 1989-2017 were identified from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) and followed until a clinically indicated angiography within 15 years was performed or death or end of follow-up occurred. The patients were divided into cohorts based on smoking status and studied with regard to plaque progression defined as the occurrence of ≥50 luminal stenosis on subsequent coronary angiogram. Results A total of 2,272,518 coronary artery segments in 215,364 patients were included of whom 48.1% were never smokers (NS), 33.4% were previous smokers and 18.5% were active smokers (S). The plaque progression incidence rate (IR) was 2.1 (2.04-2.16) per 1000 segment years (SY) for S, 1.77 (1.73-1.81) per 1000 SY for PS, and 1.33 (1.30-1.36) per 1000 SY for NS. The largest increase in plaque progression IR per 1000 SY in relation to smoking status was the middle right coronary artery (RCA) segment (NS: 1.36 (1.27-1.45), PS: (2.23 (2.08-2.39), S: 3.25 (3.01-3.51)). Kaplan-Meier curves depict increased progression in the RCA among smokers (supplementary picture 1). Discussion: In this nationwide longitudinal coronary angiography study, plaque progression occurred more frequently in smokers and in whom the right coronary artery was more commonly affected by coronary atherosclerosis.Plaque progression in RCA vs LAD